N400 and the activation of prejudice against rural migrant workers in China

Rural migrant workers (RMWs) are a special social group under the household registration system in China. Although RMWs work in the city, they are not issued a permanent city resident card, and are hardly integrated into the city life. City residents harbour strong negative stereotypes about RMWs. Facing a word-pair comprising a status noun (RMWs vs. Unban workers) followed by an adjective, 16 young participants were required to classify the adjective as being either negative or positive, while the event-related brain potentials (ERPs) were recorded. An ERP component identified as the N400 was found, and was studied with the question whether its amplitude reflected the effects of prejudice against RMWs. The reaction times to identify the positive adjectives preceded by the nouns pertaining to RMWs were significantly longer than to those preceded by nouns denoting Urban workers. The amplitude of the N400 evoked in RMW-Positive adjective condition was significantly larger than in Urban worker-Positive adjective condition, possibly reflecting the higher conflict when participants identified the adjectives as positive primed by RMWs. These findings revealed that negative stereotypes about RMWs still exist today, although Chinese mainstream media has disseminated positive messages about the RMWs for decades.

Research highlights
► We employed semantic paradigm and select Chinese words as prime and target stimuli.
► Prejudice against RMWs in China on the N400 amplitude was studied for the first time.
► We proved N400 could be reference measure of stereotype and prejudice.